This study will assess the safety, tolerability, and efficacy of MK-6913 for the treatment of moderate-to-very-severe vasomotor symptoms (hot flashes or hot flushes) in postmenopausal women. The primary study hypothesis is that one or more doses of MK-6913 will result in a significantly greater reduction from baseline, compared to placebo, in the number of moderate to very severe hot flashes after 4 weeks of treatment.